In March, Microsoft announced that their upcoming Internet Explorer 8 would: "use its most standards compliant mode, IE8 Standards, as the default."
Note the last word: default. Microsoft argued that, in light of their newly published interoperability principles, it was the right thing to do. This declaration heralded an about-face and was widely praised by the web standards community; people were stunned and delighted by Microsoft's promise.
This week, the promise was broken. It lasted less than six months. Now that Internet Explorer IE8 beta 2 is released, we know that many, if not most, pages viewed in IE8 will not be shown in standards mode by default.

How many pages are affected by this change? Here's the back of my envelope: The PC market can be split into two segments — the enterprise market and the home market. The enterprise market accounts for around 60 per cent of all PCs sold, while the home market accounts for the remaining 40 per cent. Within enterprises, intranets are used for all sorts of things and account for, perhaps, 80 per cent of all page views. Thus, intranets account for about half of all page views on PCs!

Article by Hakon Lie of Opera Software. Also note that acdcording to the European Commission, "As for the tying of separate software products, in its Microsoft judgment of 17 September 2007, the Court of First Instance confirmed the principles that must be respected by dominant companies. In a complaint by Opera, a competing browser vendor, Microsoft is alleged to have engaged in illegal tying of its Internet Explorer product to its dominant Windows operating system. The complaint alleges that there is ongoing competitive harm from Microsoft's practices, in particular in view of new proprietary technologies that Microsoft has allegedly introduced in its browser that would reduce compatibility with open internet standards, and therefore hinder competition. In addition, allegations of tying of other separate software products by Microsoft, including desktop search and Windows Live have been brought to the Commission's attention. The Commission's investigation will therefore focus on allegations that a range of products have been unlawfully tied to sales of Microsoft's dominant operating system." http://europa.eu/rapid/pressReleasesAction.do?reference=MEMO/08/19&format=HTML&aged=0&language=EN&guiLanguage=en